Find the most CPU-intensive Java threads in your current environment and locate stack information

Reference: JVM performance Tuning monitoring Tools JPS, Jstack, Jmap, Jhat, Jstat, hprof use detailed

The following is an example of the most CPU-consuming Java thread in a Java process and locates the stack information, with the command PS, top, printf, Jstack, grep.

The first step is to find out the Java process ID, the Java application name I deployed on the server is Mrf-center

[email protected]:/# ps -ef | grep mrf-center | grep -v greproot     21711     1  1 14:47 pts/3    00:02:10 java -jar mrf-center.jar

Get the process ID of 21711.

The second step is to find the CPU-intensive thread in the process

can use ps-lfp pid or ps-mp pid-o THREAD, Tid, time or top-hp pid, I use the third one here, the output is as follows:

The time column is the CPU for each Java thread, and the longest CPU time is a thread with a thread ID of 21742.

printf "%x\n" 21742

The hexadecimal value of 21742 is 54ee, which is used below.

The third step is to find the Java code for the CPU-intensive thread

It's Jstack's turn, it's used to output the stack information for process 21711, and then grep based on the thread ID's hexadecimal value, as follows:

[email protected]:/# jstack 21711 | grep 54ee"PollIntervalRetrySchedulerThread" prio=10 tid=0x00007f950043e000 nid=0x54ee in Object.wait() [0x00007f94c6eda000]

You can see the CPU consumption in the Pollintervalretryschedulerthread class of object.wait (), I looked up my code, and navigate to the following code:

//Idle wait   (). info  ( "Thread ["  + getname  () + ); schedulerthreadstate = Polltaskschedulerthreadstate. idlewaiting ; long  now = System. currenttimemillis  (); long  waitTime = now + getidlewaittime  (); long  timeuntilcontinue = Waittime-now; synchronized  (Siglock) {try  {if  (!halted. ()) {Siglock. (timeuntilcontinue); }} catch  (Interruptedexception ignore) {}}  

It is the idle wait code for the polling task, and the above siglock.wait (timeuntilcontinue) corresponds to the previous object.wait ().

Attention:
You can also redirect a thread's stack through the > command to a file by using the Jstack command, and then find the appropriate stack code in the file based on the hexadecimal value of the thread ID.

Find the most CPU-intensive Java threads in your current environment and locate stack information